1. Field of the Invention
The present invention relates to a communication terminal device, communication system, and communication method used by workers who undertake dangerous operations such as fire-fighting operations.
2. Description of the Related Art
A system is proposed in which a biosensor is worn by the body of a firefighter and biological information on the firefighter is transmitted wirelessly to a command center to monitor the safety of the firefighter on a real-time basis. For example, a firefighter is determined to be in a dangerous state if the heart rate of the firefighter is abnormal.
Patent document 1 discloses a mobile terminal for an emergency rescue support system, wherein, when abnormality of the body of a user is detected by referring to a measurement of a biological information sensor, the mobile terminal originates an emergency call to nearby mobile terminals.
Patent Document 1: JP2003-109160
If a worker is located in a place such as a scene of a fire where radio waves from a GPS satellite cannot reach, it may be possible to know that the worker is in a dangerous state by receiving biological information on the worker wirelessly but it is difficult to identify the location of the worker. It is therefore to determine which worker should be sent for a rescue.